Meeting Abstract

25.3  Friday, Jan. 4  Rapid modification of preoptic area egr-1 and vasotocin mRNA by social opportunity BURMEISTER, SS*; LEBONVILLE, CML; FERNALD, RD; Univ. of North Carolina; Univ. of North Carolina; Stanford Univ. sburmeister@unc.edu

In the cichlid fish Astatotilapia burtoni, male-male interactions determine social status which, in turn, has a number of physiological and behavioral consequences. For example, subordination can cause increases in cortisol levels and decreases in androgen levels. In addition, subordinate males do not defend territories, court females, or display the bright colors that are characteristic of dominant males. Social rank is plastic, however, and subordinate males will ascend to dominance given the opportunity. Because vasotocin is known to influence social interactions in other vertebrates, we asked whether preoptic area vasotocin neurons differ depending on social status. To do this, we manipulated social rank and the opportunity to rise in rank and measured changes in vasotocin mRNA expression using in situ hybridization. We also looked at the response of neurons to social status and changes in status by measuring expression of the immediate-early gene egr-1 in the same regions of the preoptic area. We found that in the parvocellular population, vasotocin mRNA levels were higher in subordinate males compared to dominant males whereas dominant males had higher levels of vasotocin mRNA in the magnocellular and gigantocellular populations. Interesting, we found that in the parvocellular population, males rising to dominance decreased their vasotocin mRNA levels to match that of dominant males within 20 minutes. We also found that males rising to dominance had higher levels of egr-1 mRNA within all three regions of the preoptic area while subordinant and dominant males had similar levels of egr-1. In conclusion, we found that vasotocin expression is regulated by social status and can change rapidly in response to changes in rank.